ABSTRACT
I. RADIOACTIVITY OF NATURAL PHOSPHATES The occurrence of radioactivity in natural phosphates was established by Strutt in 1906 [1] and uranium was found to be the main component. The interest shown in this element began with the nuclear era in the 1940s, when all new uranium sources were screened. The uranium content of natural phosphates of sedimentary origin was determined to be within the range 0.005 to 0.02% U and is attended primarily by its decaying products [2].
